The Effect of Time-Restricted Eating Combined with Exercise on Body Composition and Metabolic Health: A Systematic Review and Meta-Analysis

Background Time-restricted eating (TRE) is increasingly popular, but its benefits in combination with exercise still need to be determined. Objectives This systematic review and meta-analysis aimed to evaluate the efficacy of TRE combined with exercise compared with control diet with exercise in improving the body composition and metabolic health of adults. Methods Five electronic databases were searched for relevant studies. Randomized controlled trials (RCTs) examining the effect of TRE combined with exercise on body composition and metabolic health in adults were included. All results in the meta-analysis are reported as mean difference (MD) with 95% confidence interval (CI). Study quality was assessed using the revised Cochrane Risk of Bias Tool and Grading of Recommendations Assessment, Development, and Evaluation assessment. Results In total, 19 RCTs comprising 568 participants were included in this systematic review and meta-analysis. TRE combined with exercise likely reduced the participants’ body mass (MD: −1.86 kg; 95% CI: −2.75, −0.97 kg) and fat mass (MD: −1.52 kg; 95% CI: −2.07, −0.97 kg) when compared with the control diet with exercise. In terms of metabolic health, the TRE combined with exercise group likely reduced triglycerides (MD: −13.38 mg/dL, 95% CI: −21.22, −5.54 mg/dL) and may result in a reduction in low-density lipoprotein (MD: −8.52 mg/dL; 95% CI: −11.72, −5.33 mg/dL) and a large reduction in leptin (MD: −0.67 ng/mL; 95% CI: −1.02, −0.33 ng/mL). However, TRE plus exercise exhibited no additional benefit on the glucose profile, including fasting glucose and insulin, and other lipid profiles, including total cholesterol and high-density lipoprotein concentrations, compared with the control group. Conclusions Combining TRE with exercise may be more effective in reducing body weight and fat mass and improving lipid profile than control diet with exercise. Implementing this approach may benefit individuals aiming to achieve weight loss and enhance their metabolic well-being. This study was registered in PROSPERO as CRD42022353834.


Introduction
A modern lifestyle characterized by the round-the-clock availability of high-calorie foods and insufficient regular physical activity accompanied by periods of prolonged sitting significantly perturbs the circadian clock.It increases susceptibility to metabolic diseases [1].WHO recommends avoiding an unhealthy diet and exercising regularly to prevent and reduce major risk factors for noncommunicable diseases [2].Intermittent fasting (IF) has emerged as a novel approach beyond simple calorie restriction to reduce body weight and improve metabolic health [3].Time-restricted eating (TRE) is a form of IF that has emerged as a popular dietary strategy in recent years and involves confining the eating window to a specified number of hours per day and fasting with zero-calorie beverages for the remaining hours of the day [4].Notably, TRE has grown prominently as a creative and workable treatment for obesity and metabolic diseases, because it eliminates the need to track caloric intake or calorie count during the eating window, making it a convenient and straightforward approach [5].Emerging evidence suggests that modifying meal timings can prevent and manage various lifestyle-related disease states and affect a wide variety of physiological functions [6], including those linked to the circadian clock, athletic performance, skeletal muscle insulin sensitivity, and whole-body metabolic health [7].
Exercise is a well-known component of a healthy lifestyle [8], conferring benefits such as weight management, enhanced cardiovascular well-being, increased energy expenditure, improved mood, and decreased susceptibility to chronic diseases [9].Previous meta-analyses have consolidated the benefits of integrating exercise and dietary interventions, highlighting that the combined approach surpasses individual interventions in optimizing overall effects and harnessing potential health benefits [10].Several human trials [11,12] have investigated the metabolic benefits of combining TRE with exercise.In a randomized controlled trial (RCT), Haganes et al. [11] found that the combined approach of TRE and exercise resulted in a reduction in glycated hemoglobin (HbA1c) concentrations and visceral fat compared with the individual exercise or TRE groups, as well as the control group, in overweight/obese populations.Another RCT conducted by Moro et al. [12] found that TRE combined with exercise effectively reduced inflammatory markers and risk factors related to cardiovascular and metabolic diseases in healthy adults.Exercise and TRE have beneficial effects on almost all organ systems through overlapping mechanisms [13], such as the improvement of insulin sensitivity [14,15], autophagy activation [16,17], anti-inflammatory effects [18,19], and gut microbiota modulation [20,21].Therefore, combined TRE and exercise may be an effective and practical lifestyle alternative for improving overall metabolic health.
A recent meta-analysis examined the effects of IF, including TRE, and other types such as alternate-day fasting and the 5:2 diet, combined with exercise.The findings revealed that IF plus exercise led to improvements in various cardiometabolic outcomes, including body weight, blood pressure, and lipid profile, compared with a control diet plus exercise [22].However, previous meta-analyses have not comprehensively analyzed the additive effects of TRE plus exercise compared with a control diet plus exercise on body composition and multiple metabolic variables.Therefore, the purpose of this systematic review and meta-analysis was to consolidate and quantify the available data on the combination of TRE and exercise, as well as assess its efficacy in improving body composition and metabolic health compared with following a control diet with exercise.By understanding the combined effects of TRE and exercise, we can potentially enhance the development of more effective lifestyle interventions and provide personalized recommendations for individuals aiming to optimize their overall health and well-being.

Methods Registration
This systematic review and meta-analysis was registered at PROSPERO (registration number CRD42022353834) and performed following the PRISMA statement guidelines and the Cochrane Handbook of Systematic Reviews of Interventions [23].

Search strategy
All literature investigating the combined effect of TRE and exercise on body composition and metabolic health were searched and obtained utilizing PubMed, Embase, SPORTDiscus, Web of Science, and Cochrane Central Register of Controlled Trials from inception to February 2024.The search strategy included various combinations of the keywords and MeSH terms: (time-restricted feeding or time-restricted eating or intermittent fasting or time-restricted fasting or time-restricted diet or timerestricted meal) AND (exercise or physical activity or physical exercise or training or fitness or running or cycling).A detailed search strategy is presented in Supplementary Table 1.These searches were limited to human studies and full text, the papers accepted were in English language only, and no restriction was applied on the publication date.Additional studies were identified by searching the reference lists of the studies that were obtained by our systematic search.

Eligibility criteria and study selection
The study selection process is shown in Figure 1.Search results retrieved by the search strategy were imported into Endnote 20.Two authors (ZD and KW), working together, completed the initial screening of records according to the defined criteria.Once the titles and abstracts were screened, 2 authors reviewed the full texts independently and discussed discrepancies, and any disagreements between the 2 authors were resolved through discussion with a third author (RH) until a consensus was reached.The following defined inclusion criteria according to the population, intervention, comparison, outcome framework were used to select studies eligible for this systematic review and meta-analysis: 1) a population of healthy individuals aged !18 y with normal weight, overweight, or obesity; 2) RCTs or randomized crossover studies with intervention of TRE combined with all types of exercise; 3) control diet (control diet describes a diet not following the TRE pattern; different studies used various terms including habitual diet and usual diet, which describe eating habits that individuals consistently follow over time; non-TRE diet, which refers to an unrestricted eating window diet; normal dietary pattern, which describes a dietary pattern that is considered typical or standard within a given population) with the same exercise program; and

Data extraction
Extraction of data from included studies was performed by a single author (ZD) into an electronic spreadsheet (Excel, 2023) according to the following study characteristics: study information (first author, publication year, characteristics of the participants, and study design); intervention duration; TRE eating window and calorie intake; exercise type; and outcomes and main findings.Forest plots were generated by conducting metaanalyses using the postintervention means and SDs or mean differences (MDs) and their corresponding SDs for each outcome.All the outcomes were transferred to the same unit, such as body weight (kilogram), fat mass (kilogram), LDL (milligrams per deciliter), TG (milligrams per deciliter), and fasting glucose (milligrams per deciliter).In articles in which the means and SDs were not provided, we contacted the authors for the relevant data.When it was impossible to obtain adequate data due to communication failure, data were extracted from graphical representations using WebPlotDigitizer software.A second author (KW) checked all data extracted for accuracy.

Risk of bias assessment
The revised Cochrane Risk of Bias tool (RoB 2) [24] and RoB 2 additional considerations for crossover trials [25] were independently used by 2 authors (ZD and KW) to assess the risk of bias, and any disagreements were resolved by discussion with the other authors.The following aspects were evaluated for the quality of the RCTs: 1) bias arising from the randomization process; 2) bias because of deviations from the intended interventions; 3) bias because of missing outcome data; 4) bias in the measurement of the outcome; and 5) bias in the selection of the reported result.The crossover trial assessed 6 domains: randomization, period and carryover effects, deviation from the intended intervention, missing outcome data, measurement of the outcome, and selection of reported results.Moreover, each study's overall risk of bias was determined as low risk, some concerns, or high risk.

Certainty of evidence
The Grading of Recommendation Assessment, Development, and Evaluation (GRADE) assessment was used to assess the overall quality of evidence.The overall quality was assessed on the following domains: risk of bias, consistency of results across studies, directness and precision of results, and the likelihood of publication bias [26].GRADE assessments were conducted for all the outcomes included in the meta-analysis.All authors examined any disagreements before reaching a consensus.

Data synthesis and analysis
One author (ZD) performed data synthesis and analysis, and meta-analyses were completed utilizing Review Manager software (RevMan Version 5.4, Cochrane Collaboration).These analyses involved calculating MDs along with 95% confidence intervals (CIs) to assess outcomes.The MD is a standard statistic that measures the absolute difference between the mean values in 2 groups of a randomized trial.The calculations were performed using random-effects models, considering the possibility of heterogeneity in clinical or methodological factors that could have influenced the outcomes.Effect sizes were computed to assess and compare the effects of TRE combined with exercise with the control diet with exercise for the outcomes.Heterogeneity was evaluated utilizing the I 2 statistic, with a significance level set at P < 0.05.Analyses with I 2 > 50% were explored using sensitivity analyses, excluding one study at a time, to verify whether any study was responsible for heterogeneity.Subgroup analyses were performed as follows: 1) TRE calorie intake: ad libitum TRE (unrestricted energy intake within the eating window) and non-ad libitum TRE (restricted energy intake within the eating window); and 2) intervention duration (moderateterm interventions >4 wk, or short-term interventions 4 wk).Publication bias was examined with a funnel plot and Egger's test if !10 studies were included in the meta-analysis.An α value equal to 5% was adopted for all analyses.The analyses were conducted using the metal package of the software Stata v 13.0 (StataCorp).

Overview of the main findings
The main findings of the meta-analysis are summarized in the section above.The results of the subgroup analysis are listed in Supplementary Tables 2.1 and 2.2 for the TRE calorie intake and intervention duration subgroup, respectively.The tables include MDs with the corresponding 95% CIs for all subgroups separately.Significant group differences were found in TG and TC concentrations (P ¼ 0.02 and P < 0.01, respectively) for the TRE calorie intake subgroup analysis.For the subgroup analysis of intervention duration, no group differences were found.

Publication bias
We assessed publication bias to evaluate the potential impact of selective publication on the results of our meta-analysis.The variables body mass, fat mass, fat-free mass, and TC fulfilled the minimum requirement of including !10 studies, enabling a publication bias assessment (Supplementary Table 3).The Egger's linear regression test for funnel plot asymmetry was used to investigate publication bias, and funnel plots showed no indication of publication bias in body mass (0.532), fat mass (0.06), fat-free mass (0.097), and TC (0.10).

Future studies
During a search of clinicaltrials.gov,14 registries of clinical trials were identified, with the combination of TME and exercise as an intervention in different individuals.These trials are ongoing or expected to be completed between 2023 and 2027.Among these studies, different outcomes are being analyzed: body composition (n ¼ 14), glycemic profile (n ¼ 11), lipid profile (n ¼ 10), and inflammatory markers (n ¼ 4), as shown in Supplementary Table 4.

Discussion
Overall, this systematic review and meta-analysis investigated the combined effect of TRE and exercise on body composition and metabolic health in adults compared with a control diet and exercise.Outcome measures included body mass, fat mass, fat-free mass, fasting glucose and insulin, TG, TC, LDL, HDL, leptin, adiponectin, IGF-1, IL-6, and TNF-α.Two studies were categorized as having a low risk of bias [38,42], whereas the other 17 studies raised some concerns [11,12,[27][28][29][30][31][32][33][34][35][36][37][39][40][41]43].The GRADE evaluation rated 3 of the 14 outcomes from the current study as moderate quality, and the remaining 11 were classified as low and very low quality.The main results of our meta-analysis highlighted the additive effect of TRE in the presence of exercise on body composition and metabolic health, compared with exercise alone.The pooled results from the 19 articles involving 568 participants revealed that TRE plus exercise reduces body mass, fat mass, TG, LDL, leptin, IGF-1, IL-6, and TNF-α.However, no changes were observed in fat-free mass, fasting glucose, insulin, TC, HDL, or adiponectin concentrations.These findings suggest that combining TRE with exercise may effectively improve body composition and specific metabolic markers in adults.
The pooled analysis demonstrated a notable and superior effect of combining TRE with exercise in terms of reducing body mass (À1.86 kg, P < 0.01) and fat mass (À1.52 kg, P < 0.01) when compared with the control group.These findings are consistent with a previous meta-analysis that showed a significant difference in body weight between IF combined with exercise and the exercise-only groups [22].Notably, the additional reduction in body mass observed in the combined intervention did not lead to a further decrease in fat-free mass (P ¼ 0.23).Preserving fat-free mass during weight loss is crucial due to its role in regulating metabolic rate, maintaining skeletal integrity, and preserving functional capacity [44].This outcome also aligns with another meta-analysis that reported similar preservation of fat-free mass when implementing IF and resistance training to reduce body mass and body fat [45].Additionally, a systematic review combining resistance training and IF demonstrated preserved muscle mass and decreased body fat percentage [46].It is worth noting that TRE restricts the time available for calorie consumption, potentially resulting in an overall decrease in energy intake [47].During fasting, the body's stored glycogen reserves become depleted, and it starts to rely more on fat as a fuel source to meet its energy needs.This shift from using predominantly carbohydrates to using more fats for energy is known as increased fat oxidation [48].On the other hand, exercise promotes energy expenditure and stimulates fat oxidation.[32] Some concerns Some concerns Low Low Low Some concerns Lin et al., 2022 [33] Some concerns Some concerns Low Low Some concerns Some concerns Liu et al., 2023 [34] Some concerns Some concerns Low Low Some concerns Some concerns Moro et al., 2016 [36] Some concerns Some concerns Low Low Some concerns Some concerns Moro et al., 2020 [37] Some concerns Some concerns Low Low Low Some concerns Moro et al., 2021 [12] Low Some concerns Low Low Some concerns Some concerns Peeke et al., 2021 [38] Low Low Low Low Low Low Stratton et al., 2020 [40] Some concerns Some concerns Low Low Some concerns Some concerns Tinsley et al., 2017 [41] Some concerns Some concerns Low Low Some concerns Some concerns   Abbreviations: CI, confidence interval; HDL, high-density lipoprotein; IGF-1, insulin-like growth factor 1; IL-6, interleukin 6; LDL, low-density lipoprotein; MD, mean difference, TC, total cholesterol; TG, triglyceride; TNF-α, tumor necrosis factor alpha. 1 Most of the included studies exhibited some concerns in the risk of bias assessment, which may have an impact on the certainty of the findings.
2 Imprecise due to confidence intervals included potential for important harm or benefit. 3I 2 values showed high heterogeneity. 4Small sample size.
Z. Dai et al.

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The synergistic effects of these interventions likely contributed to the observed improvements in body composition compared with individual interventions.The increased fat mass loss observed in the combined intervention may be attributed to enhanced fat oxidation and a favorable metabolic shift toward an increased oxidative phenomenon [49].Further research is needed to explore the long-term effects and underlying mechanisms of this combined intervention.
In terms of the glycemic profile, the current meta-analysis revealed that the combination of TRE with exercise did not yield additional benefits on fasting glucose concentrations compared with the control group.However, notable trends were observed, particularly in the non-ad libitum and the longerduration subgroups, where reductions in fasting insulin concentrations reached statistical significance.This decrease in the insulin concentration may indicate an improvement in insulin resistance, as assessed by HOMA-IR, which takes into account fasting insulin and glucose values [50].A recent review encompassing studies involving TRE in adults with obesity reported no changes in fasting glucose concentrations after 2-12 mo of TRE [51].It is worth noting that the studies reporting reductions in fasting insulin concentrations mostly involved TRE interventions with shorter eating windows.Only one systematic review and meta-analysis have examined the combined effects of IF and exercise on glycemic markers compared with exercise alone with a control diet, and it also found no significantly greater improvements in glycemic markers, which aligns with our findings [52].The variability observed in the effects of combined TRE and exercise on the glycemic profile across different studies can be attributed to several factors.Participant characteristics play a crucial role, as some studies focused on healthy adults with normal glycemic profiles, whereas others targeted individuals with pre-existing metabolic disorders.Participants' baseline fasting glucose and insulin concentrations can significantly influence the outcomes.Additionally, differences in the design of TRE interventions, such as the duration of fasting, timing of meals, and even the composition of meals consumed before blood samples were taken, can also contribute to variations in the effects on glucose metabolism.It is important to note that TRE differs from a ketogenic or low-calorie diet, because it does not strictly limit carbohydrate intake, thereby minimizing the direct impact on blood glucose concentrations.
The effects of combining TRE with exercise on lipid profiles remain uncertain.Our analysis revealed that the implemented interventions did not impact TC and HDL concentrations.However, there was a notable decrease in LDL concentrations (8.52 mg/dL, P < 0.01) and TG concentrations (13.38 mg/dL, P < 0.01).These findings are consistent with a previous metaanalysis by Kazeminasab et al. [22], which reported a significant reduction of 5.35 mg/dL in LDL concentrations and a trend toward a reduction in TG when combining IF with exercise compared with a control diet plus exercise.Another umbrella review also highlighted the effect of TRE on LDL concentrations [53].These observations may be attributed to the influence of TRE on lipid metabolism [54].TRE has been linked to improved lipolysis and β-oxidation [55].The fasting state reduces the production of apolipoprotein B in liver cells, lowering LDL concentrations [56].Additionally, studies have demonstrated that TRE can impact the expression of genes involved in lipid metabolism [57].Studies in rodent models have shown that time-restricted feeding combined with endurance exercise can enhance fatty acid metabolism and prevent diet-induced fat mass gain [58].The objective of TRE is to maximize lipid consumption through more extended fasting periods while promoting anabolic processes and preserving lean mass [32], which aligns with our previous findings on body composition.However, other meta-analyses have reported contradictory results.Khalafi et al. [52] found no significant differences in changes to lipid profiles between exercise plus IF and exercise alone.Possible reasons for the discrepancies include variations in intervention types and study designs.These meta-analyses encompassed different forms of IF, including alternate-day fasting, 5:2 IF, TRE, and Ramadan IF, a religious form.It is an obligatory practice to refrain from eating and drinking during daylight hours daily for 29 or 39 d annually [59].Furthermore, regular exercise promotes favorable changes in lipid metabolism, such as increased lipoprotein lipase activity, which aids in TG breakdown and LDL particle clearance from the bloodstream [60].The inconsistent findings may be due to ceiling effects regarding the magnitude of improvement.Most participants in our study did not have metabolic disorders and were within a healthy range at baseline.Therefore, the combined intervention may yield more benefits for lipid profiles in individuals with cardiometabolic disorders.Further research is necessary to ascertain whether the combined intervention of TRE and exercise provides greater lipid profile improvements than individual interventions in people with dyslipidemia.
Regarding adipokines, a recent systematic review and metaanalysis examining the effects of TRE on these markers found that TRE improved leptin concentrations but did not increase adiponectin concentrations, which is consistent with our findings [19].Leptin and adiponectin are important adipokines produced by adipose tissue that play a role in maintaining whole-body metabolism.Adiponectin is associated with improved insulin sensitivity and possesses anti-inflammatory properties [61].On the other hand, increasing evidence shows that leptin modulates immune responses by increasing the secretion of various cytokines [54] and promoting immune cell activation, proliferation, and chemotaxis [62].Furthermore, the circulation concentrations of adipokines are influenced by fat mass [19,63,64].Therefore, reductions in weight and fat mass may lead to concurrent decreases in leptin concentrations and inflammation.In terms of inflammatory cytokines, there is promising evidence suggesting a large reduction in IL-6 and TNFα concentrations following the combined intervention of TRE and exercise.IL-6 and TNF-α are proinflammatory cytokines associated with chronic inflammation and metabolic dysfunction [65].TRE and exercise have independently demonstrated anti-inflammatory effects [18,66].However, it is essential to note that only 3 studies included in this systematic review and meta-analysis measured IL-6 and TNF-α concentrations.Further well-designed studies with larger sample sizes are needed to determine the effectiveness of the combined intervention of TRE and exercise on inflammatory biomarkers.
Another highlighted aspect of the present study was the subgroup analyses performed for different types of TRE based on calorie intake and intervention duration.TRE protocols are often differentiated into "ad libitum" and "non-ad libitum".Ad libitum TRE allows individuals to consume any food and does not impose calorie restrictions within the designated eating window.In contrast, non-ad libitum TRE involves specific guidelines or restrictions on food choices or calorie intake during the eating window.Our subgroup analysis revealed significant differences in TG concentrations (P ¼ 0.02) and TC concentrations (P < 0.01) between the ad libitum and non-ad libitum TRE approaches.Notably, only the non-ad libitum TRE approach demonstrated improvements.In this subgroup, studies implemented TRE with either calorie restriction [33] or isocaloric eating [12,36,37,39,42], whereas the control diet followed either the same calorie restriction [33] or isocaloric eating [12,36,37,39,42] pattern without a limited eating window.These findings highlight the importance of considering different TRE approaches' specific characteristics and guidelines, suggesting that the effect of TRE combined with exercise on TC and TG concentrations varied depending on the type of calorie intake employed.However, it is important to note that these conclusions are based on the available evidence, and further research is needed to confirm and expand on these findings.Particularly, future studies should aim for greater standardization in control diet interventions to enable direct comparisons and establish more convincing results.
The findings of this meta-analysis have important implications for understanding the potential benefits of combined interventions in improving metabolic health and body composition.By synthesizing data from 19 studies, this comprehensive meta-analysis thoroughly evaluates the available evidence.The results indicate that the combined intervention of TRE and exercise yields more substantial changes compared with a control diet with exercise.This suggests a potential synergistic effect, supporting the notion that simultaneously targeting dietary patterns and exercise may have additive or interactive benefits in enhancing body composition and metabolic health.Remarkably, our analysis highlights that the non-ad libitum TRE pattern is associated with more pronounced effects in lipid profiles.However, it is important to acknowledge certain limitations of our meta-analysis.The majority of the included studies focused on healthy and physically active individuals with normal body weights and optimized metabolic parameters.Only 6 studies [11,27,[32][33][34]38] specifically investigated the combined effect of TRE and exercise in participants with overweight/obesity who may present with abnormal metabolic parameters.Moreover, there was considerable variability in the types of exercise employed across the studies, including resistance training, endurance training, concurrent training, etc.This heterogeneity in exercise types and populations may have influenced the interpretation of the results.To address these limitations, future studies should consider comparing the effects of different exercise modalities and exploring the combined intervention in distinct population groups separately.Another limitation of our meta-analysis is the language restriction to studies published solely in English.This restriction may introduce bias, as relevant studies published in other languages were excluded from our analysis.In summary, although this meta-analysis provides valuable insights into the combined interventions of TRE and exercise, it is crucial to consider the abovementioned limitations when interpreting the results.Further research encompassing a broader range of participant characteristics, exercise types, and languages will enhance our understanding of the topic and allow for more robust conclusions.
Regarding this topic, future studies presented in our search results included 14 trials investigating the combined effect of TRE and exercise.Although specific publications for these studies have not yet been identified, we believe that they hold the potential to provide valuable insights into the effects discussed in this section.Additionally, these studies may contribute to updating the data of this meta-analysis.Furthermore, we anticipate that this review will be a significant resource for guiding future analyses of TRE and exercise interventions, particularly considering the expected increase in related publications.There is a need for future research to focus on investigating the effects of combined TRE and exercise interventions in diverse populations, encompassing individuals with metabolic disorders or sedentary lifestyles.Longer intervention durations should also be explored to understand the sustained effects on metabolic health better.Furthermore, it is crucial to identify the optimal modalities of TRE and exercise to maximize their potential benefits.Conducting studies in these areas will advance our knowledge and enhance the effectiveness of interventions targeting metabolic health.
In conclusion, our systematic review and meta-analysis provides evidence supporting the effectiveness of combining TRE with exercise in reducing body weight and fat mass, as well as improving lipid profiles.However, further research is needed to investigate the comparing effects of different exercise modalities and explore the combined intervention in distinct population groups separately.These findings have significant implications for healthcare practitioners and public health professionals, offering valuable insights into the combined effects of TRE and exercise.Implementing this integrated approach may benefit individuals aiming to achieve weight loss and improve metabolic well-being.

FIGURE 2 .
FIGURE 2. Forest plot of the effects of TRE þ EX compared with CD þ EX on body mass.CD, control diet; CI, confidence interval; EX, exercise; IV, inverse variance; SD, standard deviation; TRE, time-restricted eating.

FIGURE 3 .
FIGURE 3. Forest plot of the effects of TRE þ EX compared with CD þ EX on fat mass.CD, control diet; CI, confidence interval; EX, exercise; IV, inverse variance; SD, standard deviation; TRE, time-restricted eating.

FIGURE 4 .
FIGURE 4. Forest plot of the effects of TRE þ EX compared with CD þ EX on fat-free mass.CD, control diet; CI, confidence interval; EX, exercise; IV, inverse variance; SD, standard deviation; TRE, time-restricted eating.

FIGURE 5 .
FIGURE 5. Forest plot of the effects of TRE þ EX compared with CD þ EX on fasting glucose.CD, control diet; CI, confidence interval; EX, exercise; IV, inverse variance; SD, standard deviation; TRE, time-restricted eating.

FIGURE 6 .
FIGURE 6. Forest plot of the effects of TRE þ EX compared with CD þ EX on fasting insulin.CD, control diet; CI, confidence interval; EX, exercise; IV, inverse variance; SD, standard deviation; TRE, time-restricted eating.

FIGURE 7 .
FIGURE 7. Forest plot of the effects of TRE þ EX compared with CD þ EX on triglycerides.CD, control diet; CI, confidence interval; EX, exercise; IV, inverse variance; SD, standard deviation; TRE, time-restricted eating.

FIGURE 8 .
FIGURE 8. Forest plot of the effects of TRE þ EX compared with CD þ EX on total cholesterol.CD, control diet; CI, confidence interval; EX, exercise; IV, inverse variance; SD, standard deviation; TRE, time-restricted eating.

FIGURE 9 .
FIGURE 9. Forest plot of the effects of TRE þ EX compared with CD þ EX on HDL cholesterol.CD, control diet; CI, confidence interval; EX, exercise; HDL, high-density lipoprotein; IV, inverse variance; SD, standard deviation; TRE, time-restricted eating.

FIGURE 10 .
FIGURE 10.Forest plot of the effects of TRE þ EX compared with CD þ EX on LDL cholesterol.CD, control diet; CI, confidence interval; EX, exercise; IV, inverse variance; LDL, low-density lipoprotein; SD, standard deviation; TRE, time-restricted eating.

FIGURE 11 .
FIGURE 11.Forest plot of the effects of TRE þ EX compared with CD þ EX on leptin.CD, control diet; CI, confidence interval; EX, exercise; IV, inverse variance; SD, standard deviation; TRE, time-restricted eating.

FIGURE 12 .
FIGURE 12. Forest plot of the effects of TRE þ EX compared with CD þ EX on adiponectin.CD, control diet; CI, confidence interval; EX, exercise; IV, inverse variance; SD, standard deviation; TRE, time-restricted eating.

TABLE 1
Characteristics of the included studies (continued on next page) Z. Dai et al.Advances in Nutrition 15 (2024) 100262

TABLE 3
Overall certainty of evidence